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56 lines
1.8 KiB
C++
56 lines
1.8 KiB
C++
//===--- ProtocolDispatchStrategy.h - ---------------------------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This header declares the ProtocolDispatchStrategy enum and some
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// related operations. It's split out because we would otherwise need
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// to include MetadataValues.h in some relatively central headers.s
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_ABI_PROTOCOLDISPATCHSTRATEGY_H
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#define SWIFT_ABI_PROTOCOLDISPATCHSTRATEGY_H
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#include "swift/Basic/Unreachable.h"
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#include <cstdint>
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namespace swift {
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/// Identifiers for protocol method dispatch strategies.
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enum class ProtocolDispatchStrategy: uint8_t {
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/// Uses ObjC method dispatch.
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///
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/// This must be 0 for ABI compatibility with Objective-C protocol_t records.
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ObjC = 0,
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/// Uses Swift protocol witness table dispatch.
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///
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/// To invoke methods of this protocol, a pointer to a protocol witness table
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/// corresponding to the protocol conformance must be available.
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Swift = 1,
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};
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/// Does a protocol using the given strategy require a witness table?
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inline bool protocolRequiresWitnessTable(ProtocolDispatchStrategy strategy) {
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switch (strategy) {
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case ProtocolDispatchStrategy::ObjC:
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return false;
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case ProtocolDispatchStrategy::Swift:
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return true;
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}
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swift_unreachable("Unhandled ProtocolDispatchStrategy in switch.");
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}
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}
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#endif
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